Numerous reports said the new deal adds four years to Thomas’ existing contract, which runs through the 2014 season. That would keep him in the Emerald City for the next five years — through the 2018 season.

Thomas’ new deal is worth $40 million in base salary over those additional four years, with $27.725 million guaranteed. Rapoport added on Twitter. That would make Thomas not only the highest-paid safety, but the highest-paid defensive back on a multiyear deal.

Altogether, with a salary of $4.625 million in 2014, Thomas reportedly is slated to be paid $44.625 million over the next five years. That averages out to $8.925 million per season.

Thomas’ reported extension comes a week after rumors that the Seahawks were close to a new deal for cornerback Richard Sherman. La Canfora reiterated Monday that Sherman’s own contract extension will come soon and will likely make him the highest-paid corner in the NFL.

Together, Thomas and Sherman comprise the backbone of Seattle’s “Legion of Boom” secondary.

Now just 24 years old, Thomas will be 29 when the reported new extension ends — giving him the potential ability to sign another big contract before he turns 30. Considering the way Thomas has played in his first four years in the league, he could be due another big payday in 2019.

Thomas has started every game since the Seahawks drafted him out of Texas 14th-overall in the first round in the 2010 NFL Draft — the first draft for general manager John Schneider and head coach Pete Carroll. As a rookie, Thomas pulled in a team-leading five interceptions and tallied 71 total tackles.

The NFL took notice in 2011, sending him to the Pro Bowl after a spectacular year in which he collected 96 tackles and two picks. In 2012, Thomas was voted All-Pro and returned to the Pro Bowl after another standout season, one that included three interceptions — including one he returned for a touchdown — but a decrease in total tackles at 61.

In 2013, as Seattle powered toward the Super Bowl, Thomas finished the regular season with a whopping 129 total tackles, which led the team. His five interceptions were tied for fifth in the NFL; Sherman finished first with 8 picks. Thomas was voted All-Pro and earned a spot on the Pro Bowl roster again.